AuthorTopic: To DNG or not to DNG (Read 17863 times)

Good point - one potential disadvantage of DNGs is that (if set) the jpeg preview will be rebuilt everytime you made a change to the RAW settings. This is time consuming.

But depending on the quality set, there's a lot you can do with that JPEG. Peter Krogh showed me pretty large ink jet prints made from these JPEGs and they were quite impressive. Having that kind of data for applications that can use the JPEG and leave the Raw alone makes this an interesting workflow tool. Add DNG profiles for rendering tweaks, its really getting interesting.

Best practice - fully adjust the RAW file first and then convert to DNG once you are happy. Converting to DNG on import does not really make sense and is quite inefficient.

For some it might be best practices, for others not so much. I think a lot depends on the quantity of images you have to process, how much you can be done while you're doing something else and your limitations on storage space.

My LR catalog has less than 20K images. If I import and convert 100 images to DNG at a sitting, not a problem in my workflow. Someone doing 1000 a day, 10K a day, that's a different story. For me, I want to convert from the start of ingestion, build decent sized previews, add metadata/keywords and convert to DNG to verify to some degree, the integrity of the Raw before I format my card. I want Standard or maybe 1:1 previews built before I get started.

I've read Krogh's book and Resnick's book on workflow. I've got a lot of good ideas from each, plus my own playing around to get a system that works well for me. I recognize it could be totally counter productive for someone else. Just look at 100 photographers desktops to get an idea of their differing ideas of filing data.

For some it might be best practices, for others not so much. I think a lot depends on the quantity of images you have to process, how much you can be done while you're doing something else and your limitations on storage space.

I guess I meant 'best practice' if you are using a DNG workflow - I accept that the DNG workflow is not suited for everyone. Lot's of people shoot only jpegs, some through ignorance but some because it works best for them - many press guys I know are obliged to shoot jpeg because that's what the newspaper's photo dept has specified.

Horses for courses as they say - I find lots to like with a DNG workflow but as always, YMMV.

I guess I meant 'best practice' if you are using a DNG workflow - I accept that the DNG workflow is not suited for everyone. Lot's of people shoot only jpegs, some through ignorance but some because it works best for them - many press guys I know are obliged to shoot jpeg because that's what the newspaper's photo dept has specified.

I'm working 100% Raw. I was implying that for "my workflow", low volume, best practices are to convert to DNG as I ingest into LR. The speed hit doesn't bother me. At such a time that I'm ready to edit the images (picks, deletes, etc), I want DNG, full sized previews built as I very often zoom in at 100% to inspect sharpness. There's no question there is a processing and time hit for doing this (I usually do this when I'm away from the computer). So the speed hit isn't a speed hit for me. At such a time I'm ready to view the images, I want all that stuff over and done with, even if I end up tossing some of the DNGs into the trash.

Now here's a possible issue I need to test further. Lets say you start with a clean, virgin LR catalog. You import and convert to DNG, 100 images, ask for full sized previews which are (I believe) stored in the preview database, Catalog Previews.lrdata. Say its now 20mb in size. Now you delete 99 images. One would expect that the Catalog Previews.lrdata would shrink in size. It doesn't appear to, even using the optimize catalog settings. Of course, this doesn't appear to be a DNG issue only. When I imported DNGs and CR2's, looked at the Catalog Previews.lrdata, deleted nearly all the images from the catalog and optimized it, the Catalog Previews.lrdata didn't shrink.

Is it possible that the previews for deleted files exist until their expiration date anyway? Meaning....if you set to the preview for "delete after 30 days" that even if you delete a file that the preview will remain until it expires?

Cheers.....

Todd in Chicago

P.S. BTW....I did not get a chance to come up and say hello, but I was at the Epson Print Academy yesterday at the Hyatt.....you guys were great! Thanks for making color management even easier to understand. Great job by all and I had a wonderful, educational, and inspirational time! Hey...I hope you guys took Henry to a nice place to eat! That guy is so cool.......

Quote from: digitaldog

I'm working 100% Raw. I was implying that for "my workflow", low volume, best practices are to convert to DNG as I ingest into LR. The speed hit doesn't bother me. At such a time that I'm ready to edit the images (picks, deletes, etc), I want DNG, full sized previews built as I very often zoom in at 100% to inspect sharpness. There's no question there is a processing and time hit for doing this (I usually do this when I'm away from the computer). So the speed hit isn't a speed hit for me. At such a time I'm ready to view the images, I want all that stuff over and done with, even if I end up tossing some of the DNGs into the trash.

Now here's a possible issue I need to test further. Lets say you start with a clean, virgin LR catalog. You import and convert to DNG, 100 images, ask for full sized previews which are (I believe) stored in the preview database, Catalog Previews.lrdata. Say its now 20mb in size. Now you delete 99 images. One would expect that the Catalog Previews.lrdata would shrink in size. It doesn't appear to, even using the optimize catalog settings. Of course, this doesn't appear to be a DNG issue only. When I imported DNGs and CR2's, looked at the Catalog Previews.lrdata, deleted nearly all the images from the catalog and optimized it, the Catalog Previews.lrdata didn't shrink.

Is it possible that the previews for deleted files exist until their expiration date anyway? Meaning....if you set to the preview for "delete after 30 days" that even if you delete a file that the preview will remain until it expires?

I don't think that's useful behavior. Plus I have the preferences set for never. But I'd expect that deleted images would produce deleted previews.

Quote

P.S. BTW....I did not get a chance to come up and say hello, but I was at the Epson Print Academy yesterday at the Hyatt.....you guys were great! Thanks for making color management even easier to understand. Great job by all and I had a wonderful, educational, and inspirational time! Hey...I hope you guys took Henry to a nice place to eat! That guy is so cool.......

Now here's a possible issue I need to test further. Lets say you start with a clean, virgin LR catalog. You import and convert to DNG, 100 images, ask for full sized previews which are (I believe) stored in the preview database, Catalog Previews.lrdata. Say its now 20mb in size. Now you delete 99 images. One would expect that the Catalog Previews.lrdata would shrink in size. It doesn't appear to, even using the optimize catalog settings. Of course, this doesn't appear to be a DNG issue only. When I imported DNGs and CR2's, looked at the Catalog Previews.lrdata, deleted nearly all the images from the catalog and optimized it, the Catalog Previews.lrdata didn't shrink.

Sounds like a question for the LR User Forums. I don't use LR catalogs so cannot help.

I use Expressions Media which is why I like the DNG format. All preview thumbs and enlarged images look great since they are derived from the embedded jpeg. It's also fast this way as ExMedia does not have to do much except pull out the previews.

Here's a good time saver. If you generate a web gallery in LR from DNGs LR re-processes all the RAW data to web size images. It seems not to use the embedded previews - d'uh. Consequently it takes about 10-15 times longer to make a web gallery than Photo Mechanic or ExMedia which simply use the already converted jpeg previews. Go figure.

If there is a way to make LR use embedded previews from DNGs, even on import and preview, then I have not seen it - I'll be happy to be shown how, if it can be done. Bridge is the same, 100% previews are generated from the RAW data, no attempt is made to access the 100% size embedded previews which are surely good enough for checking sharpness etc.

Hmmmm....am I understanding that right?If you have a hi-res cam and use 1:1 previews, they will never be deleted? Is that right?

If the preview is less than half the size of the image, its deleted as we would hope. The largest preview I can set in LR is 2048. My 5D and now 5DMII are more than twice the preview requested (2048) so the high rez previews are eventually deleted.